Exposure apparatus

ABSTRACT

An exposure method for manufacture of semiconductor devices, includes moving a shutter having an edge so that the edge is related to a predetermined exposure region; projecting an exposure beam to the edge of the shutter and to at least a portion of the exposure region; determining a position of a shadow of the edge of the shutter formed by the exposure beam with respect to a predetermined coordinate system related to movement of a movable chuck; adjusting the shutter in accordance with the determination; placing a substrate on the chuck; moving the chuck so that the substrate is related to the exposure region; and controlling the exposure of the substrate with the exposure beam through the shutter.

FIELD OF THE INVENTION AND RELATED ART

This invention relates to an exposure apparatus and, more particularly,to an exposure apparatus for transferring and printing an image of anoriginal, such as a mask, onto a workpiece such as a semiconductorwafer, with high precision.

With the increasing degree of integration of semiconductor integratedcircuits, in an exposure apparatus (aligner) for manufacture of thesame, further enhancement of transfer precision is required. As anexample, for an integrated circuit of a 256 megabit DRAM, an exposureapparatus capable of printing a pattern of a linewidth of 0.25 micronorder is necessary.

As such super-fine pattern printing exposure apparatus, an exposureapparatus which uses orbit radiation light (SOR X-rays) has beenproposed.

The orbit radiation light has a sheet beam shape, uniform in ahorizontal direction. Thus, for exposure of a plane of a certain area,many proposals have been made, such as:

(1) a scan exposure method wherein a mask and a wafer are moved in avertical direction whereby the surface is scanned with X-rays of sheetbeam shape in a horizontal direction;

(2) a scan mirror exposure method wherein X-rays of a sheet beam shapeare reflected by an oscillating mirror whereby a mask and a wafer arescanned in a vertical direction; and

(3) a simultaneous exposure method wherein X-rays of a sheet beam shapein a horizontal direction are diverged in a vertical direction by anX-ray mirror having a reflection surface machined into a convex shape,whereby an exposure region as a whole is irradiated simultaneously.

The inventors of the subject application have cooperated to devise sucha simultaneous exposure type X-ray exposure apparatus, which isdisclosed in Japanese Laid-Open Patent Application No. 243519/1989.

In this type of exposure apparatus, exposure light (X-ray) has uniformilluminance in a horizontal direction (hereinafter "X direction").However, in a vertical direction (hereinafter "Y direction"), it hasnon-uniform illuminance such as depicted by an illuminance distributioncurve 1i in FIG. 3A, for example, wherein the illuminance is high at acentral portion and decreases sway from the central portion. In theproposed apparatus, a blocking member having a rectangular opening(shutter aperture) is used, and the relationship of the time moment (t)of passage and the position in the Y direction of each of two edges, offour edges defining the opening, is controlled independently as depictedin FIG. 3B, whereby the exposure time (ΔT) at each portion in anexposure region is controlled, as depicted in FIG. 3C. Morespecifically, the time period from the passage of a leading edge 1a ofthe blocking member (the preceding one of the two edges with respect tothe movement direction of the blocking member), for allowingtransmission of the exposure light (X-rays), to the passage of atrailing edge 1b of the opening of the blocking plate (the succeedingedge with respect to the movement direction of the blocking member), forinterception of the exposure light, is controlled to thereby attaincorrect and uniform exposure of the whole exposure region. In that case,the exposure quantity control is effected on the basis of an X-rayilluminance distribution curve (hereinafter "profile") in the Ydirection, such as depicted in FIG. 3A, as measured in the exposureregion.

SUMMARY OF THE INVENTION

In this X-ray exposure apparatus, however, any deviation between theaforementioned profile and an edge drive curve produces a non-negligibleeffect upon the transfer precision.

For example, if edge drive curves as depicted by solid lines 1a and 1b.in FIG. 3B, corresponding to the profile of solid line 1i in FIG. 3A,shift by Δy to the positions of broken lines 2a and 2b in FIG. 3B,respectively, corresponding to the profile of broken line 2i in FIG. 3A,then the illuminance I of the exposure light at a position y changes by"(dI/dy) ×Δy". Accordingly, in order to suppress the change inilluminance I to a quantity not greater than 0.1%, the followingrelation has to be satisfied: ##EQU1## More particularly, if theview-angle size of the exposure region in the Y direction is 30 mm, ifthe profile such as depicted by the solid line 1i in FIG. 3A isrepresented by a quadratic function which is vertically symmetric withrespect to a center line and if the lowest illuminance is 80% of thehighest illuminance, then it follows that:

    Δy<(1/1000)×[1/(0.4/15)]≃0.04(mm)

Thus, it is seen that, in order to suppress non-uniformness inilluminance to a quantity not greater than 0.1%, the shift Δy inrelative position of the exposure light to the exposure region has to bekept at a quantity not greater than 40 microns.

A deviation in the edge drive curve or profile may result from a changein the relative attitude of a SOR device and a major assembly of theexposure apparatus, in a case of SOR X-ray exposure apparatus, and,generally, it may be attributable to an error between coordinate axes ofa wafer stage and an edge driving system.

It is accordingly an object of the present invention to provide anexposure apparatus by which an exposure quantity error ΔI attributableto a relative deviation Δy between the edge drive curve and the profilecan be reduced to thereby enhance transfer precision.

In accordance with an aspect of the present invention, to achieve thisobject, there is provided an exposure apparatus, comprising: a radiationsource with non-uniformness in illuminance generally in one-dimensionaldirection with respect to a predetermined exposure region; illuminancemeasuring means for measuring an illuminance distribution in theone-dimensional direction in the exposure region and in an area adjacentthereto; shutter means having a leading edge effective to start exposurein the exposure region and a trailing edge effective to stop theexposure; a memory with a drive table for setting a drive curve for theleading and trailing edges in accordance with the measured illuminancedistribution; shutter driving means for causing the leading and trailingedges to move through the exposure region in the one-dimensionaldirection, independently of each other, in accordance with the drivetable; edge position detecting means for detecting, with an illuminancedetector of the illuminance measuring means and at different two pointsspaced in the one-dimension direction, a position of a shadow of one ofsaid leading and trailing edges; and coordinate conversion means foreffecting conversion of a coordinate system of the drive table and acoordinate system for the positioning of the illuminance detector duringthe illuminance distribution measurement, in accordance with results ofthe edge position detection.

With this structure, the position of the shadow of the edge as detectedby the illuminance distribution measuring means with respect to at leasttwo points, spaced in the direction of illuminance distribution, doescorrespond to the position of the edge, designated in terms of thecoordinate system of the drive table, as projected upon the coordinatesystem used for the measurement of the illuminance distribution.

Accordingly, it is possible to detect the relationship between thecoordinate system of the drive table and the coordinate system in themeasurement of illuminance distribution and, by converting thecoordinate system for the illuminance distribution measurement into thecoordinate system of the drive table, an error between the coordinatesystems of the illuminance distribution measurement and the drive tablecan be corrected and, as a result, non-uniformness in exposure (exposurequantity error) ΔI attributable to such error can be reduced.

The inventors of the subject application have made investigations intoan exposure apparatus of the aforementioned type to attain furtherenhancement of the transfer precision, and have found that a change inthe relative position of the exposure region and the exposure lightprovides a non-negligible effect on the transfer precision.Particularly, in the proximity exposure process, a change in the angleof incidence of the exposure light to the exposure region results indegradation of the superposing precision.

For example, if the proximity gap G between a mask and a wafer is 50microns, then, in order to suppress a superposition error Δδ due to achange in the angle of incidence to a quantity not greater than 0.002micron, the change Δθ in the angle of incidence has to be suppressed tosatisfy:

    Δθ=Δδ/G<0.002/50=4×10.sup.-5 (rad)

Namely, it has to be suppressed to a quantity not greater than 4×10⁻⁵rad.

Further, if the exposure light has a divergent angle, the angle ofincidence of the exposure light to the exposure region changes with theshift Δy of the relative position as described above. If the intervalbetween the surface to be exposed and the point of divergence (e.g. theposition of incidence of X-rays upon a divergence convex mirror of a SORX-ray exposure apparatus) is 5 m, then the quantity Δθ of change in theangle of incidence is given by:

    Δθ=Δy/5000<4×10.sup.-5 (rad)

From this change Δθ in the angle of incidence, the above-describedsuperposition error Δδ results. The superposition error Δδ in this caseappears at different portions of the surface to be exposed, as a run-outerror of distributed transfer magnifications. From the above equation,it is seen that the change Δy in the relative position has to besuppressed to a quantity not greater than 0.2 mm.

Further, if in the positional relationship between the exposure lightand the exposure region there occurs a rotational deviation Δω_(z) aboutan axis (Z axis) of the path of the exposure light, then, at a position(X, Y) on the X-Y plane having an origin on that axis, there are causedan error Δθ in the angle of incidence as well as an illuminance changeΔI and an error Δδ, equivalently as there is caused a change Δy whereinΔy=Y. cos ω_(z).

As regards the variations such as the relative positional deviation Δyand Δω_(z), one of which is attributable to an attitude change of theexposure apparatus resulting from movement of a wafer stage of about 200microns, a displacement resulting from a temperature change may be ofabout 10 microns and a displacement resulting from vibration of a floormay be about 2 microns.

It is another object of the present invention to provide an exposureapparatus by which an exposure quantity error ΔI and a superpositionerror Δδ attributable to the rotational deviation Δω_(z) can be reduced,to thereby attain further enhancement of the transfer precision.

In accordance with another aspect of the present invention, to achievethis object, there is provided an exposure apparatus, comprising: aradiation source with non-uniformness in illuminance generally in aone-dimension direction with respect to a predetermined exposure region;exposure quantity correcting means for setting an exposure timedistribution in accordance with the non-uniformness in illuminance so asto assure a substantially uniform exposure quantity in the exposureregion; illuminance distribution measuring means for measuring anilluminance distribution in the exposure region; computing means forcalculating a constant-illumination line on the basis of a measured dataof the measuring means; and paralleling means for making theconstant-illumination line and a constant-exposure-time line of saidexposure quantity correcting means parallel.

In this structure, the illuminance distribution measuring means servesto measure an illuminance distribution in the exposure region and anarea adjacent thereto, the computing means serves to calculate aconstant-illuminance line on the basis of a measured illuminancedistribution data, and the paralleling means serves to execute anoperation making the calculated constant-illuminance line and aconstant-exposure-time line determined by the exposure quantitycorrecting means parallel. By this paralleling operation, the rotationaldeviation ω_(z) can be corrected and, therefore, the exposure quantityerror ΔI and the superposition error Δδ attributable to such rotationaldeviation ω_(z) can be reduced.

It is a further object of the present invention to provide an exposuremethod and apparatus by which uniform exposure is attained and, thus, aresist pattern of uniform linewidth is assured.

These and other objects, features and advantages of the presentinvention will become more apparent upon a consideration of thefollowing description of the preferred embodiments of the presentinvention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic and diagrammatic view of an X-ray exposureapparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view, showing details of an exposure shutterdevice of the FIG. 1 embodiment.

FIGS. 3A-3C are graphs, respectively, for explaining the operation ofthe exposure apparatus of the FIG. 1 embodiment, wherein FIG. 3A showsan illuminance distribution (profile) of illumination light, FIG. 3Bshows shutter drive curves and FIG. 3C shows an exposure timedistribution.

FIG. 4 is a flow chart for explaining the coordinate system convertingoperation in the exposure apparatus of the FIG. 1 embodiment.

FIG. 5 is a flow chart for explaining the paralleling operation in theexposure apparatus of the FIG. 1 embodiment.

FIGS. 6A-6D are schematic views, respectively, for explaining detectionof constant-intensity lines in the exposure apparatus of the FIG. 1embodiment.

FIG. 7 is a schematic view for explaining edge detection in the exposureapparatus of the FIG. 1 embodiment.

FIGS. 8 and 9 are graphs, respectively, for explaining the operation ofan X-ray detector for the edge detection, in the exposure apparatus ofthe FIG. 1 embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a general structure of an X-ray exposure apparatusaccording to an embodiment of the present invention. Denoted in thedrawing at 101 is a synchrotron orbit radiation light (SOR X-ray), anddenoted at 102 is an exposure mirror having a reflection surfacemachined into a convex shape, for expanding the SOR X-ray 101, of asheet beam shape elongated in the X (substantially horizontal)direction, in the Y (substantially vertical) direction. The bundle ofX-rays from the exposure mirror 102 diverging in the Y direction isinputted into an exposure apparatus main assembly 100 as an illuminationlight (exposure beam) 103 for the exposure process.

In the exposure apparatus main assembly 100, denoted at 104 is aberyllium window for isolating an exposure X-ray input path, maintainedat a high vacuum, and a helium ambience in a chamber 105, from eachother. Denoted at 106 is an auxiliary shutter unit (movable apertureunit) comprising an endless steel (SUS) belt having openings. Itcooperates with a main shutter unit 107 of a similar structure toprovide an exposure shutter device. Denoted at 108 is a mask having apattern, to be transferred, formed thereon by use of an X-raynon-transmissive material such as gold, for example, Denoted at 109 is awafer chuck with which a wafer 110, onto which an image of the mask 108is to be transferred, can be held fixed on a wafer stage that comprisesan X stage 121 and a Y stage 122, for example. The wafer 110 is coatedwith a resist which is sensitive to X-rays. Denoted at 111 is analignment optical unit for measuring the relative positionalrelationship between the mask 108 and the wafer 110; denoted at 123 isan X stage motor for driving the X stage 121; denoted at 124 is a Ystage motor for driving the Y stage 122; denoted at 125 and 126 aremotor drivers for the X stage motor 123 and the Y stage motor 124,respectively; denoted at 127 is a stage actuator control unit forcontrolling the operations of the motor drivers 125 and 126,respectively; denoted at 128 is a laser length-measuring device formeasuring the position of the wafer stage; denoted at 129 is a mirrorfor the laser length-measurement; and denoted at 130 is a lengthmeasuring system control unit. Denoted at 131 is a central processingunit (CPU) which is communicated with a main controller 191 through acommon bus 190, to control the stage actuator control unit 127 and themeasuring system control unit 130.

Denoted at 151 is an auxiliary shutter motor for driving the auxiliaryshutter unit 106, and denoted at 152 is a main shutter motor for drivingthe main shutter unit 107. Denoted at 153 and 154 are motor drivers,respectively, for driving the motors 151 and 152 in accordance with thenumber of pulses outputted from pulse generators 155 and 156,respectively. Denoted at 157 is a subsidiary CPU which is communicatedwith the main controller 191 through the common bus 190 and which servesto control the pulse generators 155 and 156 through a local bus 158.Denoted at 161 is an X-ray detector, and denoted at 162 is a detectorsignal processing unit.

Denoted at 171 is a Y guide bar for guiding the Y stage 122, and it isfixed to a main frame 172. The main frame 172 is fixed to the chamber105 through an upper support 173 and a lower support 174. Denoted at 175is a frame base, and the chamber 105 is supported by actuators 176-178provided at three locations on the chamber top (at front side and rearleft and rear right sides of the top). The attitude of the chamber 105can be controlled by these actuators. Adjacent to these actuators176-178, there are provided three distance sensors 179-181. By measuringthrough these sensors 179-181 the distances to the frame base 175 fromthe mounting positions of these sensors, respectively, the attitude ofthe chamber 105 can be detected. Denoted at 182 is a driver for drivingthe actuators 176-178. Denoted at 183 is a main assembly attitudecontrol unit which serves to detect the attitude of the chamber 105 onthe basis of the outputs from the sensors 179-181 and to control theattitude of the chamber 105 through the drive of the driver 182.

Denoted at 191 is a main controller which serves to control theoperation of the exposure apparatus as a whole through the common bus190, in accordance with the content memorized in a memory 192.

FIG. 2 is a perspective view schematically showing the exposure shutterdevice, comprising the auxiliary shutter unit 106 and the main shutterunit 107 of FIG. 1, as well as some elements necessary for explainingthe function of the exposure shutter device. In non-exposure period, theexposure beam 103 is blocked in the auxiliary shutter unit 106, as shownin FIG. 2, by an auxiliary shutter belt 201 which is provided by a steelbelt made of stainless steel. In the exposure period, on the other hand,the exposure beam 103 goes through a front opening 202 formed in theauxiliary shutter belt 201 as well as a rear opening 203 of theauxiliary shutter belt, moved to a position approximately opposed to thefront opening 202, and the exposure beam arrives at a main shutter belt221 of the main shutter unit 107 disposed behind the auxiliary shutterbelt 201. Like the auxiliary shutter belt 201 of the auxiliary shutterunit 106, also the main shutter belt 221 is provided with two openings,namely, a front opening 222 and a rear opening (not shown). Theabove-described function of controlling local exposure time at each ofdifferent portions of the exposure region in the Y direction isaccomplished by controlling, at each portion in the Y direction, thetime period from the passage, through that portion, of a leading edge223 of the front opening 222 of the main shutter belt 221 to the passageof the trailing edge (not shown) through that portion, so as to providean inversely proportional relationship between the time period and theilluminance of X-rays. In other words, the time period is so controlledthat, at different portions in the Y direction, the quantity of energyabsorption by the resist applied to the wafer is regular and correct.

The auxiliary shutter belt 201 is tensioned between an auxiliary shutterdriving drum 204, driven by the auxiliary shutter motor 151, and anauxiliary shutter idler drum 205, and it is driven through the frictionbetween the inside surface of the shutter belt 201 and the outsidesurface of the driving drum 204. In order to assure stable driving ofthe shutter belt 201 so as to avoid snaking, the driving drum 204 iscrowned such that the diameter at the central portion of the drum withrespect to the widthwise direction is made larger by 50-100 microns thanthe diameter at the end portion. The shutter belt 201 is provided withsmall rectangular slits 208 and 211, formed in the neighborhood of theleft-side and right-side edges thereof, for the position detection andthe timing detection, respectively. These slits cooperate with aphotointerruptor 209 and a reflection sensor 210, respectively, toproduce a start signal for the driving of the auxiliary shutter motor151 to be made in accordance with a predetermined drive pattern, or todiscriminate whether the exposure beam 103 is allowed to pass or isblocked.

The main shutter device has a similar mechanical structure as of theauxiliary shutter device, described above.

Denoted at 231 is a pinhole formed in a front face of a detectionportion of the X-ray detector 161, which is mounted to the X stage 121(see FIG. 1).

X-ray intensity profile such as at 1i (2i) in FIG. 3A can be measured bybringing the two shutter units 106 and 107 into open states,respectively, and by moving the Y stage 122 (see FIG. 1) so as toscanningly displace the X-ray detector 161 in the Y direction within theexposure view angle (exposure region). On the basis of measured data,drive tables 1a and 1b (2a and 2b) such is shown in FIG. 3B for theleading edge 223 and the trailing edge 107 can be prepared, andcorrected drive such as shown in FIG. 3C for attaining constant quantityof energy absorption by the resist in the exposure region can beexecuted.

In this case, the X-ray intensity profile measurement is made on thebasis of a coordinate system of the X-ray detector 161 (X-Y coordinatesystem of the wafer stage, comprising X stage 121 and Y stage 122, asmeasured through the laser length-measuring device 128). On the otherhand, the corrected drive of the shutter is made on the basis of ashutter drive coordinate system (x-y coordinate system of the drivetable). For this reason, if there is a deviation between thesecoordinate systems, it is not possible to accomplish proper drivecorrection. In the present embodiment, in consideration thereof, after adrive table representing the position (Y) versus passage time (t)relation of each edge with respect to the wafer stage coordinate systemis prepared on the basis of the profile measured data, the relationshipbetween the wafer stage coordinate system and the shutter drivecoordinate system is detected and conversion is made to the positioncoordinate of the edge, from a coordinate value Y with respect to thewafer stage coordinate system into a coordinate value y with respect tothe shutter drive coordinate system. By this, the drive table isconverted into a table that represents the position (y) versus passagetime (t) relation of the edge with respect to the shutter drivecoordinate system, and, as a result, precise exposure quantitycorrection is assured.

The details of such coordinate system conversion in this exposureapparatus will now be explained. The coordinate system conversion may beexecuted together with the profile measurement, at the time ofassembling of the exposure apparatus, at the time of setting of the sameor at the time of maintenance thereof (in maintenance mode).

Referring to the flow chart of FIG. 4, first, at step 401, the mainshutter belt 221 is stopped at such a position that, as shown in FIG. 7,the leading edge 223 of the opening 222 of the main shutter belt 221blocks a portion of the exposure view angle. It is assumed that theshutter drive coordinate at this time is y_(N). In FIG. 7, denoted at701 is an illuminance detecting area corresponding to the exposure viewangle; denoted at 702 is a high-precision reflection type sensor at themain shutter unit 107 side (see FIG. 1); denoted at 703 is a slit whichis cooperable with the high precision reflection type sensor 702 todetermine an origin of the coordinate system representing the positionof the edge 223; and denoted at 704 is the shadow of the edge 223. Atstep 402 in FIG. 4, the wafer stage is moved so as to scanninglydisplace the X-ray detector 161 in the Y direction to thereby detect thewafer stage coordinate (the position with respect to the illuminancedistribution measurement coordinate system) Y_(N) of the shadow 704 ofthe edge 223 (FIG. 7).

FIG. 8 illustrates the relationship between the Y-direction position ofthe pinhole 231 of the X-ray detector 161 and the output of the X-raydetector 161 In this drawing, reference character Y_(N) denotes theposition of the shadow of the edge 223, and a broken line depicts theexposure profile to be defined in the region blocked by the shutter 221,which otherwise is exposed with the exposure beam 103 when the shutteris open. Enlarging the portion near y_(N). in FIG. 8 in the Y direction,the change in the output depending on the relationship between theshadow Y_(N) of the edge and the pinhole 231 at the front face of theX-ray detector 161 is such as shown in FIG. 9. In FIG. 9, referencecharacter P_(O) denotes the position of the pinhole 231 just at themoment as the pinhole 231 goes out of the shadow 704 of the edge 223.Reference character P_(N) denotes the position of the pinhole 231 atwhich the center of the pinhole coincides with the shadow 704 of theedge 223. Reference character P_(S) denotes the position of the pinhole231 just at the moment as the pinhole 231 is completely shaded by theshadow 704 of the edge 223. It is seen from FIG. 9 that accurately theposition Y_(N) of the shadow 704 of the edge is at the middle point (ΔY₁=ΔY₂) between a coordinate ΔY_(O) corresponding to the position P_(O)and a coordinate Y_(S) corresponding to the position P_(S). In thisembodiment, in consideration thereof, the middle point between thecoordinate Y_(S) at the rise of the output of the X-ray detector 161 andthe coordinate Y_(O) at the saturation point of the detector output isdetermined as the coordinate (edge position) Y_(N) corresponding to theend line of the shadow 704 of the edge 223.

When the pinhole 231 is at the position P_(N), the output of the X-raydetector 161 is not always equal to a half of the output when thepinhole 231 is at the position P_(O), i.e., E₁ ≠E₂. This is because theat the output component based on the edge position and the componentbased on the illuminance distribution (profile) are not discriminatedseparately.

Referring back to FIG. 4, at step 403, the motor 152 is driven so thatthe leading edge 223 is moved to a position, blocking another portion ofthe exposure view angle 701, namely, to a position of a shutter drivecoordinate y_(M). Then, at step 404, like step 402, a wafer stagecoordinate Y_(M) of the shadow 704 of the edge 223 is detected.

When the wafer stage coordinates Y_(N) and Y_(M) corresponding to theshutter drive coordinates y_(N) and y_(M) at two different points in theexposure view angle 701, spaced in the Y direction, are detected in themanner described above, then at step 405, the coordinate of the edgeposition in the drive table of edge position Y) versus passage time (t)relation with respect to the wafer stage coordinate system, having beencalculated on the basis of the profile measured data and having beenstored in the memory 192, is converted from a coordinate Y with respectto the wafer stage coordinate system into a coordinate y with respect tothe shutter drive coordinate system, by using the following equation:

    y=y.sub.N +(Y-Y.sub.N)×(y.sub.M -y.sub.N)/(Y.sub.M -Y.sub.N)

By this, the drive table is converted into one that represents theposition (y) versus passage time (t) relation of the edge with respectto the shutter drive coordinate system. Then, by using the obtainedtable, the main shutter unit 107 is controlled and the exposure processof the wafer 110 to the mask 108 with the exposure beam 103 is executed.The table obtained by the conversion is stored in into the memory 192.

In the foregoing example, the shadow of the leading edge 223 is detectedand the coordinate system of the illuminance distribution detector isconverted into a coordinate system of the edge drive table. However, inplace of detecting the shadow of the leading edge 223 of the opening 222of the main shutter belt 221, the shadow of the trailing edge may bedetected and the coordinate system conversion may be made accordingly.

Next, a description will be provided of a paralleling operation of theexposure apparatus. Such a paralleling operation may be executed at thetime of assembling of the exposure apparatus, at the time of setting ofthe exposure apparatus or at the time of maintenance of the apparatus(in maintenance mode).

Referring to the flow chart of FIG. 5, first, at step 501, while holdingthe shutter in its open state, the wafer stage is moved to scanninglydisplace the X-ray detector 161 in the X and Y directions, and anilluminance distribution of a part of or the whole of the exposure viewangle 601 is measured. At step 502, from measured data, a line or linesof constant illuminance (constant-intensity lines) are detected. FIGS.6A-6C show examples of manner of scan. Since the exposure beam 103 (seeFIG. 1) has non-uniformness in intensity substantially only in the Ydirection, where as shown in FIG. 6A the scan is made along a path 602which includes a small distance in the Y direction at a rightward endportion of the illuminance detection plane 601 as well as a smalldistance in the Y direction at a leftward end portion of the illuminancedetection area and when a straight line 605 is drawn to connect points603 and 604 having the same measured values of illuminance, then theline 605 provides a constant-intensity line. FIG. 6B shows an examplewherein, as compared with the scan method shown in FIG. 6A, theY-direction scanning lengths at the leftward and rightward portions areincreased so as to obtain a larger number of constant-intensity lines605a -605e. FIGS. 6C and 6D show examples wherein, as compared with thescanning methods of FIGS. 6A and 6B, a larger number of Y-directionscanning lines are used. By using multiple measuring points forobtaining a single constant-intensity line, even in the case where aconstant-intensity line is not straight, an approximate straight linecan be drawn on the basis of a least square method or the like todetermine the constant-intensity line with a reduced error. In FIG. 6,denoted at 601 is the illuminance detecting area; denoted at 602 is thepath of scan of the X-ray detector 161; denoted at 603 and 604 are thosepoints at which the X-ray detector 161 produces outputs of the samelevel; and denoted at 605 and 605a-605e are constant-intensity lines.

Then, at step 503 in FIG. 5, the main shutter motor 152 is driven tomove and stop the main shutter belt 221 at a position at which, as shownin FIG. 7, the leading edge 223 of the opening 222 of the main shutterbelt 221 blocks a portion of the exposure view angle 701. In FIG. 7,denoted at 701 is the exposure view angle of a size corresponding to orslightly smaller than the illuminance detecting area 601 in FIG. 6. Theilluminance detecting area 601 is so set that it is larger than theexposure view angle 701 at least with respect to the Y direction andthat the whole exposure angle 701 is included inside the illuminancedetecting area 601, so as to allow measurement of the illuminance at aportion around the exposure view angle 701 through the X-ray detector161. Denoted at 702 is a high-precision reflection type sensor at themain shutter unit 107 side (see FIG. 1), and denoted at 703 is a slitwhich is cooperable with the high-precision reflection type sensor 702to determine the origin of a coordinate system representing the positionof the edge 223. It is to be noted here that, at step 503, in place ofusing the leading edge 223 of the opening 222 of the main shutter belt221, the trailing edge (not shown) thereof may be used to block aportion of the exposure view angle. Subsequently, at step 504, the X-raydetector 161 on the wafer stage is used to measure the position of theshadow 704 of the edge 223 in the Y direction, at two different pointsspaced in the X direction, to thereby detect any inclination of the edgeshadow 704 with reference to the X axis Y axis) of the X Y plane.

FIG. 8 illustrates the relationship between the Y-direction position ofthe pinhole 231 of the X-ray detector 161 and the output of the X-raydetector 161. In this drawing, reference character Y_(N) denotes theposition of the shadow of the edge 223, and a broken line depicts theexposure profile to be defined in the region blocked by the shutter 221,which otherwise is exposed with the exposure beam 103 when the shutteris open. Enlarging the portion near y_(N) in FIG. 8 in the Y direction,the change in the output depending on the relationship between theshadow Y_(N) of the edge and the pinhole 231 at the front face of theX-ray detector 161 is such as shown in FIG. 9. In FIG. 9, referencecharacter P_(O) denotes the position of the pinhole 231 just at themoment as the pinhole 231 goes out of the shadow 704 of the edge 223.Reference character P_(N) denotes the position of the pinhole 231 atwhich the center of the pinhole coincides with the shadow 704 of theedge 223. Reference character P_(S) denotes the position of the pinhole231 just at the moment as the pinhole 231 is completely shaded by theshadow 704 of the edge 223. It is seen from FIG. 9 that accurately theposition Y_(N) of the shadow 704 of the edge is at the middle point (ΔY₁=ΔY₂) between a coordinate Y_(O) corresponding to the position P_(O) anda coordinate Y_(S) corresponding to the position P_(S). In thisembodiment, in consideration thereof, the middle point between thecoordinate Y_(S) at the rise of the output of the X-ray detector 161 andthe coordinate Y_(O) at the saturation point of the detector output isdetermined as the coordinate (edge position) Y_(N) corresponding to theend line of the shadow 704 of the edge 223.

When the pinhole 231 is at the position P_(N), the output of the X-raydetector 161 is not always equal to a half of the output when thepinhole 231 is at the position P_(O), i.e., E₁ ≠E₂. This is because theoutput component based on the edge position and the component based onthe illuminance distribution (profile) are not discriminated separately.

In the manner described above, the edge position Y_(N) is detected atleast at two locations including the leftward and rightward end portionsin the X direction. Subsequently, at step 505 in FIG. 5, from theresults of detection of the edge position Y_(N) and theconstant-intensity line or lines 605 determined beforehand, anyinclination of the leading edge 223 or the trailing edge 207 in the X-Yplane with respect to the constant-intensity line 605 is determined. Atstep 506, discrimination is made as to whether the inclination of theedge 223 with respect to the constant-intensity line 605 is not greaterthan a predetermined inclination. If not, the paralleling operation isfinished. If on the other hand the inclination is greater than thepredetermined inclination, the sequence goes to step 507 whereat drivequantities for the actuators 176 -178 (FIG. 1) necessary for theparalleling of the edge 223 with the constant-intensity line 605, arecalculated. Then, at step 508, these actuators 176-178 are driven and,after this, the sequence goes back to 501 and the operations at steps501-506 are repeated. After completion of the paralleling operation, thewafer 110 is exposed to the mask 108 with the exposure beam 103, whilebeing controlled by the main shutter 107.

While the foregoing description has been made of an exposure apparatuswherein the exposure beam 103 comprises SOR X-rays, the presentinvention is not limited thereto but is applicable also to an exposureapparatus which uses an exposure beam comprising g-line light, i-linelight, an excimer laser light or the like.

While the invention has been described with reference to the structuresdisclosed herein, it is not confined to the details set forth and thisapplication is intended to cover such modifications or changes as maycome within the purposes of the improvements or the scope of thefollowing claims.

What is claimed is:
 1. An exposure apparatus, comprising:a radiationsource generating a non-uniformness in illuminance including x-raysgenerally in a direction in one dimension with respect to apredetermined exposure region; illuminance measuring means for measuringan illuminance distribution in the direction in one dimension in theexposure region and in an area adjacent thereto; shutter means having aleading edge effective to start exposure in the exposure region and atrailing edge effective to stop the exposure; a memory with a drivetable for setting a drive curve for the leading and trailing edges inaccordance with the measured illuminance distribution; shutter drivingmeans for causing the leading and trailing edges to move through theexposure region in the direction in one dimension, independently of eachother, in accordance with said drive table; edge position detectingmeans for detecting, with an illuminance detector of said illuminancemeasuring means and at two different points spaced in the direction inone direction, a position of a shadow of one of the leading and trailingedges; and coordinate conversion means for effecting conversion of acoordinate system of said drive table and a coordinate system for thepositioning of said illuminance detector during the illuminancedistribution measurement, in accordance with results of the edgeposition detection.
 2. A method of adjusting a shutter device of anexposure apparatus having a movable chuck for holding a substrate to beexposed, and an exposure region related to the exposure of thesubstrate, said shutter device having a movable shutter with a leadingedge and a trailing edge, said method comprising the steps of:moving theshutter so that one of the leading and trailing edges of the shutter isrelated to the exposure region; projecting an exposure beam includingx-rays between the leading and trailing edges of the shutter and to atleast a portion of the exposure region; determining a position of ashadow of the one edge formed by the exposure beam with respect to astage coordinate system related to the movement of the chuck; andadjusting the shutter on the basis of the determination in saiddetermining step.
 3. A method according to claim 2, wherein saidadjusting step comprises the step of determining the relationshipbetween a position of the edge with respect to a shutter coordinate, setin relation to the shutter, and a position of the shadow with respect tothe stage coordinate system.
 4. A method according to claim 2, whereinsaid adjusting step comprises the step of adjusting at least one of aposition and an attitude of the shutter with respect to the exposurebeam.
 5. A method according to claim 2, wherein the exposure beamincludes at least one of light of a g-line, light of an i-line, light ofan excimer laser and light of X-rays.
 6. An exposure method for themanufacture of semiconductor devices, comprising the steps of:moving ashutter having an edge so that the edge is related to a predeterminedexposure region; projecting an exposure beam including X-rays to theedge of the shutter and to at least a portion of the exposure region;determining a position of a shadow of the edge of the shutter formed bythe exposure beam with respect to a predetermined coordinate systemrelated to movement of a movable chuck; adjusting the shutter inaccordance with the determination in said determining step; placing asubstrate on the chuck; moving the chuck so that the substrate isrelated to the exposure region; and controlling the exposure of thesubstrate with the exposure beam through the shutter.
 7. An exposureapparatus, comprising:a chuck for holding a substrate to be exposed; astage for moving said chuck in accordance with a stage coordinatesystem; a shutter having an edge, for controlling exposure of thesubstrate, held by said chuck, with an exposure beam including X-rays; ashutter driving mechanism for displacing said edge of said shutter inaccordance with a shutter coordinate system; a first detector fordetecting the exposure beam and producing a corresponding output; asecond detector for determining a position of a shadow of said edge ofsaid shutter formed by the exposure beam, with respect to the stagecoordinate system, on the basis of the output of said first detector;and a processor for determining the relationship between a position ofsaid edge of said shutter with respect to the shutter coordinate systemand the position of the shadow of said edge of said shutter with respectto the stage coordinate system, on the basis of the determination bysaid second detector.
 8. An apparatus according to claim 7, wherein saidchuck and said first detector are movable as a unit with said stage. 9.An apparatus according to claim 7, wherein the exposure beam includes atleast one of light of a g-line, light of an i-line, light of an excimerlaser, and light of X-rays.
 10. An exposure apparatus, comprising:achuck for holding a substrate to be exposed; a stage for moving saidchuck in accordance with a stage coordinate system; a shutter having anedge, for controlling exposure of the substrate, held by said chuck,with an exposure beam including X-rays; a shutter driving mechanism fordisplacing said edge of said shutter in accordance with a shuttercoordinate system; and a detector for determining, with respect to thestage coordinate system, a position of a shadow of said edge of saidshutter formed by the exposure beam which edge is positioned withrespect to the shutter coordinate system.
 11. An apparatus according toclaim 9, further comprising an adjuster for adjusting an attitude ofsaid shutter with respect to the exposure beam, in accordance with thedetermination made by said detector.
 12. An apparatus according to claim10, wherein the exposure beam includes at least one of light of a g-linelight of an i-line, light of an excimer laser, and light of X-rays. 13.A shutter adjusting method for use in an exposure apparatus for themanufacture of semiconductor devices, for adjusting a shutter with anedge, comprising the steps of:projecting the edge of the shutter on apredetermined plane with an exposure beam including X-rays; detecting aposition of the projected edge of the shutter; and adjusting the shutterin accordance with the detection in said detecting step.
 14. A methodaccording to claim 13, wherein the exposure beam includes at least oneof light of a g-line, light of an i-line, light of an excimer laser, andlight of X-rays.
 15. A method according to claim 14, wherein the lightof X-rays is produced from a synchrotron radiation source.
 16. A methodof patterning a substrate through exposure of the substrate whilecontrolling the exposure with a shutter having an edge, said methodcomprising the steps of:projecting the edge of the shutter on apredetermined plane; detecting a position of the projected edge of theshutter; adjusting the shutter on the basis of said detection in saiddetecting step; and exposing the substrate with radiation includingX-rays while controlling the exposure through the adjusted shutter. 17.A method according to claim 16, wherein the radiation includes at leastone of light of a g-line, light of an i-line, light of an excimer laserand light of X-rays.
 18. A method according to claim 17, wherein thelight of X-rays is produced from a synchrotron radiation source.